UK Caving

TECHNICAL FORUMS => Film & Photography => Topic started by: JoW on December 27, 2019, 11:45:46 am

Title: Long exposure photo advice
Post by: JoW on December 27, 2019, 11:45:46 am
Can anyone offer any top tips for long exposure photos please? Mine all come out slightly blurry. I'm using a tripod and a remote shutter so the camera shouldn't be moving but they're still slightly out of focus...
Title: Re: Long exposure photo advice
Post by: grahams on December 27, 2019, 12:30:04 pm
We need more information i.e. what are the camera settings, type of camera and lighting. I assume LED, given that you mention long exposure.

I use a Sony A6000 in a cheap Meike dive case. The Sony is incredibly good a making sense of challenging lighting conditions in auto mode and almost always produces a perfect exposure with perfect focus. I place the camera on a lightweight tripod with a two second delay before the shutter fires. This allows the system to settle down after pressing the shutter button.

I always ensure that the LED lighting is away from the camera to avoid scatter from steam. Sharply defined features illuminated from the side help autofocus. The LEDs need to be set up to ensure that no areas are burned out.

If your camera has long exposure noise reduction, you should ensure that the feature is turned on. When using very long exposures, the in-camera processing for this feature is lengthy but produces great results.

Your example photo might be out of focus because the camera cannot focus correctly due to low light levels (assuming you're using auto focus). Also, that image does not have any sharply defined features within the central portion of the image on which the camera can focus. Moving the side lighting (which is very nicely done) to illuminate the features in the central part of the image, might have solved the problem in this case.

It's also possible that, depending on your setup, the camera is for some reason selecting a small aperture. This would result in diffraction blur.
Title: Re: Long exposure photo advice
Post by: JoW on December 27, 2019, 12:59:24 pm
Thank you for the info, sorry I forgot to say which camera. I'm using an olympus tg4 on live composite mode, and yes with led lighting. I am generally trying to use light painting to light larger areas.

I don't have many options for settings within this mode, though I have found a general setting for auto focus options which I'll have a play with to see if it helps.
Title: Re: Long exposure photo advice
Post by: JoW on December 27, 2019, 01:00:12 pm
Also another example:
Title: Re: Long exposure photo advice
Post by: Pitlamp on December 27, 2019, 01:12:53 pm
I wonder if this topic might be vaguely related to your question:

(I'm thinking - wider angle lens, get nearer, better illumination, so more reliable auto-focus?)

Also, if you're "painting" with light, I'd have thought that keeping the lamp in a fixed position (on a tripod maybe?) whilst constantly altering the angle it's shining at, might help?

Other than that - brighter lamps / more of them? (There are some very cheap, incredibly bright lamps intended for bicycle use available these days, on Amazon, etc.)

One other thought; if you use a makeshift Fresnel lens (which could be as simple as a thin white plastic bag) over the lamp, to spread the light, you might not need to move the lamps at all.)

But don't take any of my suggestions too seriously as I'd be the first to admit that I'm a rubbish photographer.  ;)
Title: Re: Long exposure photo advice
Post by: Pete K on December 27, 2019, 04:35:01 pm
This looks to me like it has not focussed properly prior to opening the shutter. Were you lighting the scene to get focus (half press) before opening the shutter? You can light the subject up, focus the camera with the half press and then press the OK button to lock the focus. That way you can get the camera focussed on where you want using max light available, lock it, then turn the focussing light off before you open the shutter and then light paint away as required. I have never used a remote release cable on my TG4, just the above process opening the shutter initially in the dark.
I use a TG4 and have had a few shots like this. When in focus, the Live Composite pictures are stunning.
Another thing that springs to mind, your shutter release cable could be causing some wobble on your tripod unless it is rock solid. If you are holding it while you paint, or let it hang after opening the shutter, it could be moving the camera slightly and that could be the culprit. I have found this issue with my bigger camera shooting at night and have moved to just setting a few seconds of delay on the shutter after the button is pressed and hardly use the remote release at all now.
Title: Re: Long exposure photo advice
Post by: The Old Ruminator on December 27, 2019, 06:25:37 pm
I am not sure what has happened with the above. This is a TG4 shot in Live Composite Mode. It was done very quickly. I am wondering if all is well with the camera. Its a simple process requiring little in the way of technique. Have a few trial runs in a dark garden and see if you can address what is going wrong.

( ( ( by Nicholas Chipchase (, on Flickr
Title: Re: Long exposure photo advice
Post by: Rob on December 27, 2019, 07:42:44 pm
Are these examples that you've uploaded the full resolution versions from the camera? If so, they are very small, only a few MPs. Might explain the low quality.

Otherwise, I'd also guess poor focusing during setting up...
Title: Re: Long exposure photo advice
Post by: mudman on December 27, 2019, 09:30:10 pm
Make sure you turn off image stabilisation. I believe that it can get confused in these situations.
Title: Re: Long exposure photo advice
Post by: JoW on December 28, 2019, 02:35:35 am
Thanks for all the advice, I have some things to try out - I'll have a go with the focusing option and turning off the image stabilisation. I'm using my phone and the olympus app as a remote shutter via the camera WiFi, as I initially thought the focus issue was due to me moving it slightly when I press the button. Photos on other modes are coming out OK so hopefully it's not the camera.

The examples are downloaded from camera to phone so may not be at full resolution, but I'll double check that too.

I'm happy to know other people have had success with the same camera so hopefully I can get it to work!
Title: Re: Long exposure photo advice
Post by: ZombieCake on December 28, 2019, 08:59:47 am
Can also use the self timer if no remote or cable release. Camera should have stopped shaking due to pressing the shutter after a couple of seconds or so. Stomping around near a light weight tripod can also induce shake.
Title: Re: Long exposure photo advice
Post by: JoshW on December 28, 2019, 09:08:58 am
I can’t see any real issue with blurring due to shake, I’d put it all down to the focussing!
Title: Re: Long exposure photo advice
Post by: The Old Ruminator on December 28, 2019, 09:54:01 am
To be honest the colour rendition is all wrong too. You can get similiar results with the TG 4 on I Auto when it ramps up the ISO to around 1,000. Look at the image properties to see if the ISO is given. I use the Sky Ray hand torch which seems to have a good colour and a very high light output. The Freem's use them too for video. The Scurion works well too. The above image of mine was done in a rush with just my son and me present. Of course, a multi slave flash set up would be better as would a distant person for perspective and scale. Pay careful attention to your " painting " as the image builds on the viewfinder go over any dark bits. A sort of flicking motion works best.
LCM requires more user input in-studio shots and fireworks etc. Have a look at a few online guides like this one though it does make it all sound confusing.

In a cave make sure that the focus square is set at half shutter. Full shutter then gives you the base layer on which the composite images build. You will need some ambient light to get the correct focus. After that continue light painting until the image looks OK. The camera will then go into the busy mode to set the image. Any too bright areas mean that its best to bung the shot and start again. After a while, it becomes almost second nature. In any case the camera is doing most of the work.

I think it more down to your lighting rather than focus as that is the easy bit.

You can do a little bit to the final image with with Photoshop but LCM does not take kindly to it.
Title: Re: Long exposure photo advice
Post by: The Old Ruminator on December 28, 2019, 10:28:43 am
I put most of my images on Flickr. The Flickr engine does seem to perk images up a bit. There you can access the image details. My photo above used an aperture of 2.8 and a modest 320 ISO.
Title: Re: Long exposure photo advice
Post by: JoW on January 13, 2020, 01:34:44 am
Thanks everyone, I have achieved better results on the last couple of trips - what seems to have worked is making sure the camera is focused on something with a light before I start. I'm still having trouble getting the camera to focus sometimes so maybe the camera is getting a bit well used (it also sometimes steams up on the inside of the lens)

Here's a recent effort which seems better (in this case a brighter light also helped)
Title: Re: Long exposure photo advice
Post by: The Old Ruminator on January 13, 2020, 08:31:27 am
I took the liberty of running the image through Photoshop. Used auto colour correction and auto haze adjustment then uploaded it through Flickr. I wont know if any difference until it comes up here.

( ( ( by Nicholas Chipchase (, on Flickr

Your image was about 600 kb . Its worth saving them higher say 2mb but that will reduce on social media sites. You should not have any mist inside a TG lens as they are waterproof. If you have there is not much hope for the camera. There is a tendency for LCM images to look flat as the lighting comes from the front. I want to try lighting from other angles but never seem to have the people to help. In any case, I now have two Yongnuo adjustable slave guns which work admirably with the TG camera. Blanking off the on camera flash as discussed here on other threads and Skyray spot torches works very well and takes no longer than LCM.

This with a single Yongnuo and a Skyray spot on the main feature. I could have had a Yongnuo in the background but I like blackness there to accentuate the lit parts. Anyway, it was their trip so I could only rush the photography.

( ( ( by Nicholas Chipchase (, on Flickr
Title: Re: Long exposure photo advice
Post by: The Old Ruminator on January 13, 2020, 08:34:31 am
Well as you see it took a bit of the flatness out of the image though ultimately its all a matter of taste.
Title: Re: Long exposure photo advice
Post by: Alex on January 13, 2020, 12:35:31 pm
I generally get by with a 90 quid waterproof digital camera that has night mode and starry night mode. I then put it on a tripod and then use my helmet light and occasional other lights the light up the scene. I take my camera in, in a small otter box because if it does get wet its very hard to get the lens clean and smear free especially if there is mud. When that happens I get photos like yours. So my advice is simply check the lense is clean and try and keep it clean.

For smaller passages and less muddy caves I am starting to get quite good results on my phone now!